ApacheBench

ApacheBench (ab) is an open source tool for benchmarking your
Apache
Hypertext Transfer Protocol (HTTP) server. It is designed to give you
an impression of how your current Apache installation performs. This
shows you how many requests per second your Apache installation can
serve.

The ab tool comes bundled with the
standard Apache source distribution. ab is distributed in the
apache2-utils package in Ubuntu. The package includes other useful
software for webservers such as logresolve, htpasswd, htdigest,
rotatelogs, and split-logfile.